Molding machines



April 1960 T. K. HUTCHINSON ETAL 2,931,080

MOLDING MACHINES Filed April 2, 1956 5 Sheets-Sheet 2 FIG. 4

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MOLDING MACHINES Filed April 2. 1956 s Sheets-Sheet 3 69 7/ 20 n! 87 Us /N I/EN TOR-f moms K HUTCHI/VJOIV 0. c. KEMP flUTC/f/MSO/V MOLDING MACHINES Thomas K. Hutchinson and O. C. Kemp Hutchinson, Alton, Ill.

Application April 2, 1956, Serial No. 575,417 3 Claims. o1. 22-9 This invention relates to improvements in molding machines. More particularly, this invention relates to improvements in molding machines that can form shell molds.

It is therefore an object of the present invention to provide an improved molding machine for making shell molds.

This invention is an improvement on the shell molding machine disclosed and described in our copending application Ser. No. 377,419 which is entitled Molding Machines and which was filed August 31, 1953, and which was granted September 3, 1957, as Letters Patent No. 2,804,661.

In making a shell mold, an admixture of sand and heat-responsive binder is placed on a heated pattern and left there long enough to interact and form the shell mold. The shell mold will usually be formed in a molding machine, and that machine will usually place an excess of sand and heat-responsive binder on the heated pattern; the excess of sand and binder making certain that a full-thickness shell mold is formed. Once the shell mold has been formed, the excess sand and binder are removed.

It is convenient and desirable to apply the sand and binder to the heated pattern by permitting the admixed sand and binder to fall onto that pattern under the infiuence of gravity. In the molding machine of our said copending application, the mixture of sand and binder is held in a container until that container is rotated to an inverted position; and thereupon the admixed sand and binder fall from that container onto the heated pattern under the influence of gravity. In most instances the mixture of sand and binder will come to rest on the pattern in the form of a layer of uniform density. However, where the pattern has some sizable projections on its upper surface, the admixed sand and binder may be less dense on one side of those projections than it is on the other. This variation in the density of the admixed sand and binder is due to the fact that the container is rapidly rotated to releasing position, and the sand and binder tend to retain enough of their rotative component to move sideways as they fall downwardly; and the sand and binder at the lee side of the projections will be less dense. This is objectionable because it tends to keep the shell molds from having completely uniform densities throughout. The present invention overcomes this objection and makes it possible to obtain shell molds of completely uniform densities by substantially eliminating the sideways movement of the falling sand and binder. As a result, the sand and binder fall substantially vertically and are able to form a shell mold that is just as dense on the lee side of tall projections as it is on the opposite side of those projections, even though the admixed sand and binder fall from a container that was rapidly rotated into releasing position. It is therefore an object of the present invention to provide a shell molding machine wherein the sand and binder are held in a rapidly rotating container but are directed onto a heated States Patent pattern through substantially vertical paths after they are released from that container.

The present invention assures substantially vertical movement of the admixed sand and binder, as they fall fromthe container, by equipping that container with guide plates or louvers. Those guide plates or louvers are mounted so they are substantially vertical when the container releases its sand and binder. Further, those guide plates or louvers are set so they are transverse of any sideways paths that the sand and binder would tend to follow because of their rotative components. As a result, the guide plates or louvers hold the sand and binder for substantially vertical movement. It is therefore an object of the present invention to provide the rapidly rotatable container of a shell molding machine with guide plates or louvers that are substantially vertical when that container releases its sand and binder, and to dispose those guide plates or louvers transversely of any sideways paths which the sand and binder might tend to follow because of their rotative components. I

The guide plates or louvers in the container of the shell molding machine provided by the present invention also help hold the admixed sand and binder against shift: ing prior to the time that the container releases that sand and binder. For example, in the said copending application, the binder and sand could tend to shift sideways as the container is rapidly rotated toward releasing position. Any such shifting is prevented by the guide plates or louvers of the present invention; and as a result a more uniform application of sand and binder is attained.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing and accompanying description a preferred embodiment of the present invention is shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the-invention and that the invention will be defined by the appended claims.

In the drawing,

Fig. 1 is a partially sectioned, partially broken away, plan View of a shell molding machine that is made in accordance with the principles and teachings of the present invention, and it indicates the motor diagrammatically,

Fig. 2 is a sectional view in elevation of the container of Fig. l, and it is taken along the plane indicated by the line 2-2 in Fig. 1,

Pg. 3 is a sectional view of a part of the shell molding machine of Fig. l, and it is taken along the plane indicated by the line 33 in Fig. 1,

Fig. 4 is a longitudinal sectional view of a part of the gnotofi shaft used in the shell molding machine of Fig:

Fig. 5 is a sectional View of the shell molding machine of Fig. l, and it is taken along the plane indicated by the line 55 in Fig. l; but the patternm'o'unt of Fig. 1 has been rotated three hundred and sixty degrees from" the position shown in Fig. 1.

Referring to the drawing in detail, the numeral 20 denotes one of the side plates of a shell molding machine that is made in accordance with the principles and teach ings of the present invention. The numeral 21 denotes the other side plate of that machine, and those side plates are held in rigidly spaced relation by structural ele ments, not shown, at the bottoms thereof. A hearing housing 2'2 is bolted or otherwise secured in position on the outer face of side plate 21; and that side plate has an opening formed through it to receive an inwardly extending portion of that bearing housing. An antiafriction bearing 23 is mounted within the bearing housing 22;

and a retaining plate 24 is provided to press against, and hold stationary, the outer race of that bearing.

The retaining plate 24 also serves as an inlet for compressed air which is supplied to the shell molding machine. That air will be conducted to the retaining plate 24 by a pipe, not shown, that has a threaded end seated in the threaded air inlet opening 26 in the retaining plate 24. The retaining plate 24 is annular in configuration, and it has an annular groove 27 at its inner surface. The opening 26 communicates with the annular groove 27, as emphasized particularly in Fig. 3. O-rings 29 are seated in annular grooves that are disposed on opposite sides of the annular groove 27.

The retaining plate 24 and the bearing housing 22 are annular; and they receive and telescope over a hollow shaft 28. That shaft is supported by the inner race of the anti-friction bearing 23; and it engages the O-rings 29 to provide two axially-spaced seals. An air passage 30 is formed in the wall of the shaft 28, and that passage extends from an opening in register with annular groove 27 to an opening 32. The latter opening will receive a pipe fitting to which an air line is connected; and that air line extends to the air cylinder 168 of the shell molding machine. This arrangement enables air to be transmitted from the opening 26 to the opening 32, without appreciable loss, whether the shaft 28 is rotating or is stationary. The shaft 28 has an annular groove at its exterior which receives an O-ring 31. That O-ring coacts with the bearing housing 22 to keep sand from working its way outwardly along the shaft 28 and into the hearing 23.

A cup-like cap 33 is suitably secured, as by screws or bolts, to the retaining plate 24; and a gasket 35 is positioned between that plate and that cap. A street L 37 is mounted in a threaded opening in the cap 33; and that L is suitably connected to a source of gaseous fuel by a pipe, not shown. As a result, gaseous fuel will pass into the cap 33 from the L 37, and will then flow through the interior of the hollow shaft 28.

A flange 34 is formed on the inner end of the shaft 28,

and that flange is bolted to one of the two sides 36 of the pattern mount of the shell molding machine. Those sides are rigidly held in spaced apart relation by channels 104 to which they are welded. The plates 36 coact with the channels 104 to provide a sturdy and rigid mount for a pattern-receiving frame 42. A projection 38 is formed integrally with the said one side 36 of the pattern mount, and a similar projection 38 is formed integrally with the other side 36 of the pattern mount. Each of the projectrons 38 has an opening through it, and those openings telescope over and receive a shaft 120. Set screws, not shown, seat in the projections 38 and prevent rotation or shlfting of that shaft relative to the projections 38. The pattern-receiving frame 42 is oblong in plan, and it has a support 43 extending between the midpoints of the longer sides thereof. Those longer sides rest upon the upper flanges of the channels 104, and they have openings therein that can be aligned with openings in the upper flanges of the channels 104.

The other side 36 of the pattern mount of the shell molding machine has an internal annular gear 44 rigidly secured to its outer face. The teeth of that gear engage and are driven by the teeth on the gearsection of a combined gear and coupling 46. That gear and coupling extends through an opening in the side plate and it is annular in configuration and receives the projecting end of a hollow motor shaft 48 of a motor 248. A keyway, not shown, is provided at the inner surface of the gear and coupling 46; and that keyway receives a key, not shown, which is seated in a keyway in the exterior of shaft 48. The gear and coupling 46 coact with the internal annular gear 44 to provide a driving connection between the motor 248 and the pattern mount that will operate satisfactorily despite minor misalignments between the axes of that motor and that pattern mount.

Further, the annular gear 44 coacts with the combined gear and coupling 46 to enable the bearings of the motor 248 to support the left hand side of the pattern mount, as that pattern mount is viewed in Fig. 1. This decreases the cost of the shell molding machine by eliminating a bearing housing and a hearing.

The pattern-receiving frame 42 receives a pattern plate 40; and that plate is usually referred to as a cope and drag match plate. That plate rests in a shoulder in the sides and ends of the frame 42 and on the top of the support 43 of that frame. A pattern-clamping frame 41, that is similar to the pattern-receiving frame, overlies the pattern plate 40. A support 39 extends between the midpoints of the long sides of the frame 41, and that support is in register with the support 43 of frame 42. Bolts and nuts 45 extend through aligned openings in the frames 41 and 42 and in the upper flanges of channels 104 to hold the pattern plate 40 against dislodgment.

A pair of elongated arms 50 are provided with offset ends 52. Those offset ends are thicker than the rest of the arms, and each of those offset ends is provided with an opening. The openings in the offset ends 52 of the arms 50 are aligned with each other, and those openings telescope over and receive a sleeve 122. That sleeve telescopes over and rotates relative to the shaft 120. The sleeve 122 is welded to the offset ends 52 of the arms 50; and the arms 50 and the sleeve 122 must be set between the projections 38 before the shaft is passed through the openings in those projections. However, once the sleeve 122 has been aligned with the openings in the projections 38, the shaft 120 can be telescoped into position; and thereafter that shaft will hold the arms 50 and the sides 36 for simultaneous rotation relative to itself.

Generally square plates 53 are bolted, welded or otherwise suitably secured to the outer faces of the arms 59; and those plates carry stub shafts or pivots 54. Grooved wheels 136 are rotatably mounted on the stub shafts 54 and those wheels engage and are guided by tracks 138. Each of the tracks 138 has an arcuate section, and-each of those tracks has a straight section tangent to the arcuate section. The tracks are provided with frustotriangular wheel-receiving surfaces; and those surfaces extend into the grooves of the wheels 136. The tracks are disposed inwardly of the side plates 20 and 21 of the shell molding machine; and those tracks are held in rigidly spaced relation with those side plates by spacers 142. v The arms 50 are held in rigidly spaced apart relation by the sleeve 122 and by angles 144 that are suitably secured to those arms as by welding. The angles 144 coact with the arms 50 to form an open-type rigid frame; and that frame supports a container 56 for admixed sand and binder. Such a container is referred to as a dump box or investment box. That container is elongated in the depth-Wise sense, and it telescopes freely between the spaced apart arms 50 and the spaced apart angles 144. A pair of angles 58 is suitably secured to the exterior faces of two of the sides of the container 56; and those angles are in register with the angles 144. Openings, not shown, are formed in the angles 58 and 144; and those openings are in register with each other. Bolts 60 extend through those aligned openings; and nuts 62 are threaded onto the threaded ends of those bolts. The nuts 62 and the bolts 60 hold the container 56 in assembled relation with the frame that is formed by arms 50 and angles 144.

Prior to the time the bolts 60 are passed through the openings in the angles 144, helical compression springs 64 are telescoped over the threaded ends of those bolts. In actual practice, the threaded ends of the bolts will be passed through the openings in the angles 58, the helical springs will be telescoped over those threaded ends, the container 56 will be placed so the threaded ends of the bolts 60 enter the openings in the angles 144, and then the springs 64 will be compressed until the threaded ends of the bolts 60 proje ct far enough beyond the angles 144 to receive the nuts 62 Those nuts can be tightened as desired to provide the required spring tension. That tension should be great enough to cause the container 56 and the arms 50 to move as a unit whenever that container is not engaging the pattern-clamping frame 41 supported by the pattern mount. That spring tension must not, however, be so high that the container 56 can not move relative to the arms 59 when that container engages that pattern-clamping frame.

A number of guide plates or louvers 66 are suitably connected at their ends to mounting plates 68. The guide plates or louvers are closely spaced, and they are parallel to each other and to the long sides of the container 56. A cross bar 70 is secured to one edge of each of the guide plates or louvers. Those guide plates or louvers will be vertical when the container 56 releases its sand and binder; and they will cause the sand and binder to follow substantially vertical paths as they fall from the container 56. The guide plates or louvers 66, the end plates 68, and the cross bar 70 constitute a rigid frame; and that frame fits neatly within the container 56. Screws 72 extend through the end plates 68 and seat in the short sides of the container 56 to hold the said rigid frame in position.

The guide plates or louvers 66 will be spaced from the open end of the container 56 a goodly distance. This arrangement provides a sizable space in the container 56 into which even very tall projections on pattern plate 40 can extend. The guide plates or louvers 66 will, however, be deep enough to provide full resistance to sideways shifting of the admixed sand and binder. As a result, those guide plates or louvers will hold the sand and binder against shifting movement despite the fact that the container is rapidly rotated to sand-releasing positions; and thereafter those guide plates or louvers will confine that sand for substantially vertical movement as it falls onto the pattern.

Angles 74 are secured to all of the sides of the container 56, and those angles define a rigid reinforcement for the open end of that container. In addition, the angles 74 support a non-metallic frame 76. A strip 77 of heat-resistant resilient material, such as synthetic rubber, is stapled or otherwise secured to the frame 76. The strip 77 on the frame 76 engages the pattern-clamping frame 41 whenever the container 56 is moved to sandreleasing position; and the resulting engagement prevents the loss of sand. The non-metallic nature of the frame 76 is desirable because it will resist the transfer of heat from the pattern-clamping frame 41 to the container 56; and it will therefore keep the admixed sand and binder from setting or caking in the container 56.

The pattern plate 40 is heated by burning gaseous fuel adjacent its under surface. That fuel passes through the hollow shaft 28 and is conducted to a lower manifold 51 by a conduit 49. The manifold 51 is suitably secured, as by tack welds, to angles 55; and those angles are secured to side plates 36 by screws 57 and to the webs of channels 104 by nuts and bolts 59.

The manifold 51 is oblong in plan, and it has a partition, not shown, at the midpoint of one of its longer sides. The top of that manifold has several ports 63 formed in it; and those ports communicate with an upper manifold 64. The upper manifold and the lower manifold are welded together, and the lower manifold sup'- ports the upper manifold. The gaseous fuel passes upwardly through the ports 63 and passes through the sides and ends of the'upper manifold. That upper manifold has the form of an oblong, but it has a middle arm connected to the midpoints of the long sides thereof. Partitions, not shown, are provided in the upper manifold 64 to control the flow of fuel in that manifold. One Of the partitions in the upper manifold is above and in register with the said partition in the lower manifold 51; and the other two partitions 65 are at the opposite end of the middle arm of the upper manifold. The sides and ends of the upper manifold 64 have a number of closely adjacent burner tips 67 at their inner faces, and the middle arm of that manifold has a number of closely adjacent burner tips 67 at both of its inclined upper faces. For clarity of showing, only a few of those tips have been shown.

A plate 69 of bright metal such as stainless steel is disposed below the level of the burner tips 67, and a plate 71 of insulating material such as asbestos is disposed below the plate 69. Spacers 73 extend between the pattern plate 40 and the plates 69 and 71 and hold the latter plates in rigidly spaced relation below the former plate. Sleeves 75 of insulating material enclose and protect the spacers 73.

The numeral 166 denotes a bracket that extends be. tween the'bottom flanges of channels 104. That bracket, which is preferably formed as a casting, is U-shaped in end view. The bracket 166 has a central opening in it; and that opening receives the right circular cylinder 168 referred to above. A packing gland 167 is mounted in the upper end of the cylinder 168; and that gland has a flange that projects outwardly and overlies those portions of casting 166 which define the opening 165. Screws 164 extend through openings in the flange of gland 167 and seat in threaded openings in the casting 166. A groove 169 is provided at the interior of the gland 167, and that groove receives an O-ring, not shown.

The packing gland 167 is telescoped over a piston 170 before it is telescoped into the cylinder 168; but once this has been done, a ring-carrying annulus 172 is pressed onto the lower end of that piston. The joint between the annulus 172 and the piston 170 is sealed by an O-ring mounted in an annular groove 176 in the piston 170. A compression ring, not shown, will be mounted in an annular groove 174 in the annulus 172; and that ring will bear against the inner surface of the cylinder 168. A suitable inlet and outlet, not shown, are provided for the cylinder 168; and a flexible conduit, not shown, is connected to that inlet. An electrically operated air valve will be connected between that flexible conduit and the opening 32 in the shaft 28. I

A plate 178 is suitably secured to the lower end of the piston 17d, and that plate will keep the annulus 172 in assembled relation with that piston. A plate 179 is secured to the lower end of the cylinder 168; and the air inlet for the cylinder 168 is closely adjacent the plate 179. The plate 179 is rectangular in plan, and it pr0- ects outwardly beyond the periphery of the cylinder 168. Bolts, not shown, extend between the plate 179 and the flange of the gland 167 to hold that gland and cylinder in assembled relation.

A platform 171 is mounted on the upper end of the piston 176, and that platform has openings, not shown, in it. Spacers 181 with threaded openings in the bottoms thereof are set over those openings, and screws 1 83 extend through the openings in platform 171 and seat in the threaded openings in the spacers 181. Those screws hold the spacers 181 tightly against the platform 171. The upper ends of the spacers 181 engage and support a stripper plate 187. That plate will move with the platform 171; and that plate confronts the bottom of the pattern plate 40. Whenever compressed air is introduced into the cylinder 168, the platform 171 and the stripper plate 187 will move toward the pattern plate 40. Suitable stripper pins are mounted on the plate 187, and the upper ends of those pins are disposed in openings in the pattern plate 40. Consequently, those pins can respond to air-induced movement of piston 1'70 and platform 171 to engage the shell mold on the pattern plate and free it from that pattern plate.

A guard extends from each end of the bracket 166; and that guard overlies the plate 179 that closes the lower end of the cylinder 168. That .guard protects the operator from the sharp edges of theplate 179, and of the bolts 7 and nuts used to hold the gland 167 and the cylinder 168 in assembledrelation.

A recessed metal disc 190 is suitably secured to the end of the motor shaft 48 that projects from the far side of the motor 248. A flat'disc 191 of insulating material is placed in the recess of disc 190. The disc 1% is provided with a central circular contact 102, a concentric annular contact 104 and a larger diameter concentric annular contact 106 mounted on it; and a separate lead, not shown, is connected to each of those contacts. A plate 198 of insulating material is suitably secured to the end bell of the motor 248, and that plate supports three brush holders 200, 202 and 204. Those brush holders are of standard design and construction, and they resiliently urge brushes into engagement with the contacts 102, 104 and 106, respectively. Spacers 206 hold a guard 208 in protecting position adjacent the brush holders 200, 202 and 204.

The pattern mount and the container 56 normally occupy the position shown in Fig. 1. In that position, the upper surface of the pattern plate 40 is exposed, and the open end of the container 56 is up. The container 56 will have a mixture of sand and binder in it; and as indicated particularly by the dotted line in Fig. 2, the level of the sand and binder will be intermediate the tops and bottoms of the guide plates or louvers 66.

The pattern plate 40 will be heated by the burning of the gaseous fuel that issues from the burner tips 67; and the heat from that pattern plate will cause any admixed sand and binder placed on that plate to form a shell mold. That sand and binder is placed on that pattern plate by rotating the pattern mount and the container 56 to the position shown in Fig. 5; all as explained in detail in the said copending application. While the container 56 is being rotated from the position of Figs. 1 and 2 to the position of Fig. 5, the sand in that container will tend to shift sideways because that container is rotated rapidly. However, the guide plates or louvers 66 will coact with centrifugal force on the sand to efiectively prevent any such sideways movement. As the container 56 approaches its sand releasing position, the centrifugal force will decrease sharply, and the sand and binder will start to fall toward the heated pattern plate; and that sand and binder will retain enough of its rotation-induced momentum to tend to follow inclined, rather than vertical, paths. The guide plates or louvers 66 will lie athwart those paths and will resist this tendency; and hence they will force the sand and binder to fall toward the pattern plate in substantially vertical paths.

, Because the sand and binder fall in substantially vertical paths, the sand and binder are able to form a layer of uniform density atop the heated pattern plate. This is desirable because it leads to the formation of shell molds of homogeneous nature. The uniform density of sand molds provided by the present invention is independent of the height of the projections on the pattern plate because the sand and binder have little or no sideways motion as they fall onto the pattern. Hence, high quality shell molds are assured under all circumstances. The problem of forcing the sand and binder to fall in substantially vertical paths is difficult because the container 56 has to be rotated so rapidly that centrifugal force can keep the binder and sand from falling onto the heated pattern until the container stops in inverted position. This means that the container 56 must move from its normal position to its inverted position in approximately two seconds. The speed of this movement generates rotative components in the sand and binder that tend to make that sand and binder fall sideways as well as downward. However, the guide plates 66 effectively limit any such sideways movement.

The pattern plate 40 could, if desired, be heated as taught in the said copending application; or, if desired, it could be heated by Calrod heaters as taught by our application Serial No. 575,419, now abandoned, for Molding Machines, filed of even date. In either event, the cap 8 33 and the street L would be eliminated, and the spiral conductors of said applications would be substituted for them.

The leads from the contacts 200, 202 and 204 are suitably connected to the electrically operated air valve referred to above, and to an electrically operated vibrator. The vibrator will be mounted on the pattern mount and will be energized as'the sand and binder are falling onto the pattern. That vibrator will help provide homogeneous shell molds. One of the three leads will be a common, and the others will be separately controlled by suitable switches or relays.

After the shell mold has been formed, it must be freed from the pattern; and this is done by the stripper pins 175. The electrically operated air valve will be energized to permit air to force the piston upwardly; and thereupon the pins will move upwardly and ease the shell mold off of the pattern. A headed bolt 210 extends upwardly through an opening in casting 166 and seats in platform 171; and the head of that bolt can engage the underside of that casting and limit the upward movement of that platform, and thus of the stripper pins 175. If a very short movement of the stripper pins is dsired, shorter bolts 210 could be used, or sleeves could be telescoped over the bolts 210 adjacent the heads thereof.

Whereas the drawing and accompanying description have shown and described a preferred embodiment of the present invention, it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What we claim is:

1. In a molding machine that has a frame, a patternreceiving support to hold a heated pattern, a container that has onevend thereof open and that has the other end thereof closed and that can receive and hold a mixture of sand and heat-responsive binder, a motor that can rotate said container relative to said frame, said motor being adapted to normally hold said container in an at-rest position wherein said open end of said container is up and said closed end of said container is down and wherein said mixture of sand and heat-responsive binder is adjacent and is supported by said closed end of said container, said motor being capable of being energized to rotate said container from said at-rest position to an inverted position wherein said container is above said heated pattern and wherein said open end of said container is .down and said closed end of said container is up, said motor being capable of being de-energized as said container reaches said inverted position to hold said container in said inverted position and thereby permit said mixture of sand and heat-responsive binder to fall downwardly toward said open end of said container and come to rest upon said heated pattern, said motor subsequently being capable of being re-energized to to tate said container from said inverted position to said at-rest position, and said motor thereafter being capable of being de-energized to hold said container in said atrest position, the improvement that comprises a plurality of guide plates mounted in said container, said guide plates and said container being held against movement relative to each other, said motor being adapted to rotate said container from said at-rest position to said inverted position at a speed high enough to enable centrifugal force to hold said mixture of sand and heat-responsive binder in said container and adjacent said closed end of said container, said guide plates being closely spaced and being substantially parallel to each other and to one of the sides of said container, said guide plates being substantially vertical whenever said container is in said inverted position, whereby said mixture of sand and heat-responsive binder can move downwardly toward said open end of said container and toward said heated pattern in substantially vertical paths whenever said container is held in said inverted position by said motor.

2. In a molding machine that has a frame, a patternreceiving support to hold a heated pattern, a container that has one end thereof open and that has the other end thereof closed and that can receive and hold a mixture of sand and heat-responsive binder, a motor that can rotate said container relative to said frame, said motor being adapted to normally hold said container in an at-rest position wherein said open end of said container is up and said closed end of said container is down and wherein said mixture of sand and heat-responsive binder is adjacent and is supported by said closed end of said container, said motor being capable of being energized to rotate said container from said at-rest position to an inverted position wherein said container is above said heated pattern and wherein said open end of said container is down and said closed end of said container is up, said motor being capable of being de-energized as said container reaches said inverted position to hold said container in said inverted position and thereby permit said mixture of sand and heat-responsive binder to fall downwardly toward said open end of said container and come to rest upon said heated pattern, said motor subsequently being capable of being re-energized to rotate said container from said inverted position to said at-rest position, and said motor thereafter being capable of being de-energized to hold said container in said at-rest position, the improvement that comprises a plurality of guide plates mounted in said container, said guide. plates and said container being held against movement relative to each other, said motor being adapted to rotate said container from said at-rest position to said inverted position at a speed high enough to enable centrifugal force to hold said mixture of sand and heat-responsive binder in said container and adjacent said closed end of said container, said guide plates being spaced inwardly from said open end of said container to define a space that can accommodate and can telescope over projections on said heated pattern, said guide plates being substantially vertical whenever said container is in said inverted position.

3. In a molding machine that has a frame, a patternreceiving support to hold a heated pattern, a container that has one end thereof open and that has the other end thereof closed and that can receive and hold a mixture of sand and heat-responsive binder, a motor that can rotate said container relative to said frame, said motor being adapted to normally hold said container in an atrest position wherein said open end of said container is up and said closed end of said container is down and wherein said mixture of sand and heat-responsive binder is adjacent and is supported by said closed end of said container, said motor being capable of being ene"r gized to rotate said container from said at-rest position to an inverted position wherein said container is above said heated pattern and wherein said open end of said container is down and said closed end of said container is up, said motor being capable of being de-energized as said container reaches said inverted position to hold said container in said inverted position and thereby permit said mixture of sand and heat-responsive binder to fall downwardly toward said open end of said container and come to rest upon said heated pattern, said motor subsequently being capable of being re-energized to rotate said container from said inverted position to said at-rest position, and said motor thereafter being capable of being de-energized to hold said container in said at-rest position, the improvement that comprises a plurality of guide plates mounted in said container, said guide plates and said container being held against movement relative to each other, said motor being adapted to rotate said container from said at-rest position to said inverted position at a speed high enough to enable centrifugal force to hold said mixture of sand and heat-responsive binder in said container and adjacent said closed end of said container, said guide plates being parallel to the axis of rotation of said container and being transverse of the paths of movement which the rotative components of said mixture of sand and heat-responsive binder tend to make said mixture of sand and heat-responsive binder follow, whereby said mixture of sand and heat-responsive binder can fall downwardly in substantially vertical paths when said motor halts said container in said inverted position.

References Cited in the file of this patent UNITED STATES PATENTS Canada May 3, 1955 

